This invention is concerned with improvements relating to microtomes.
In known microtomes a specimen holder may be provided having a specimen clamping mechanism for clamping a specimen to be cut. The specimen clamping mechanism is moved vertically up and down relative to a cutting knife which cuts the specimen during the downward movement of the specimen clamping mechanism. The specimen clamping mechanism is movable between an uppermost position in which it is above the cutting knife, and a lowermost position in which it is below the cutting knife.
In addition to this vertical movement the specimen clamping mechanism is also movable horizontally towards and away from the cutting knife between a rearmost position and a forwardmost position. In the rearmost position the specimen clamping mechanism is at its furthest horizontal distance from the cutting knife, and in the forwardmost position the specimen clamping mechanism is at its closest horizontal distance to the cutting knife.
In known rotary microtomes a mechanical drive is provided for executing a rough feed movement of the specimen clamping mechanism along the horizontal towards the cutting knife, and for executing a rough return movement of the specimen clamping mechanism along the horizontal away from the cutting knife. The mechanical drive may also be able to provide a rough cutting thickness adjustment of the specimen clamping mechanism towards the cutting knife along the horizontal after each cut has been made.
This kind of mechanical drive may include a movable shaft connected to a hand wheel located outside the microtome. In order to actuate the rough feed the hand wheel must be manually actuated. However, this manual actuation involves a high outlay and is inconvenient to operate.